The present invention relates to a dental color system that comprises primary colors and mixed colors with assigned coordinates in the CIElab color space, in which the coordinates of the colors of natural teeth are located essentially within an ellipsoid-shaped space, which is assigned a longitudinal axis or a baseline extending from light to dark in the CIElab space.
The invention further relates to a method for producing dental prosthesis colors for a dental prosthesis surrounded by a remaining set of teeth utilizing primary and/or mixed colors with coordinates in the CIElab color space, in which the colors of natural teeth are essentially located on coordinates within an ellipsoid-shaped space, which is assigned a longitudinal axis or a base line extending from light to dark in the CIElab space, whereby the color of the remaining teeth is determined in coordinates in the CIElab color space.
Dental restoration in the form of for example crowns or bridges are usually manufactured of a supporting skeleton material, consisting of a metal, an alloy, or high-strength ceramics, which is faced with a tooth-colored plastic and/or ceramic material. To satisfy aesthetic requirements, the color of the restoration must be matched to the color of the natural remaining teeth. For the purpose of ensuring an approximate match, facing materials are offered in several tooth colors. Tooth-shaped samples are produced for the available tooth colors and are combined into so-called color indicators. These indicators are used to select the facing material appropriate for the given case. The number of available tooth colors is limited to ensure manageability of the selection sample and to keep stock keeping costs low. Thus, indicators from leading manufacturers contain 16 to 26 colors. However, this limitation has the disadvantage that in many cases the tooth color of the dental restoration is not matched to the color of the remaining teeth to the necessary degree.
To avoid this disadvantage, one ideally would have available a color system that covers the color space of natural teeth to an extent that is tailored to the color-distinguishing ability of a normal-sighted person. However, in this case the number of colors would be so great that it would no longer be possible to provide a practical selection sample. Moreover, a color indicator that depicts all colors would no longer be manageable.
Already in practical use is a VITAPAN 3D master color system, which places its focus on the most common tooth colors. The available dental prosthesis colors are selectively arranged in planes, which in the CIElab color space are situated in an ellipsoid-shaped space taking the shape of an upright banana, which comprises the usually occurring natural tooth colors. To determine a color for the prosthesis, one determines in a first step the brightness level and in a second step the color depth. In a subsequent third step the color hue is determined. Samples of correspondingly colored teeth are available for this.
Dental color indicators with a multitude of sets of color templates are known from EP-A-0 147 232 and EP-B-0 591 958. Here, the coordinates of color samples of each respective set are located on a plane of constant lightness, which extends perpendicular relative to the L axis of the CIElab coordinate system. The first primary colors of the parallel extending plane(s) are situated on a common straight line, which extends at an offset relative to the L axis. Every color template originates from a mount embodied in fan-like fashion.
U.S. Pat. No. 6,030,209 specifies the use of a spectrophotometer to determine and select the color hue of a dental prosthesis. The teeth surrounding the dental prosthesis to be manufactured are illuminated with varying illumination and the reflected light is analyzed, correcting for ambient light. Subsequently, several coloring substances are selected from the available ones and are mixed in order to obtain the desired shade of color for the dental prosthesis.
EP-B-1 068 841 concerns a dental color system with a multitude of different color samples that are regularly spaced with regard to lightness, color saturation, and hue on at least one triangular column in the CILAB color space.